Two scientists who placed a bet 12 years ago that gravitational waves would be discovered before 2010 said last week's announcement was worth much more than any winnings.

The findings came six years too late for Professor Sheila Rowan and Professor James Hough, who put the £25 wager on in 2004 that researchers at the Laser Interferometer Gravitational Wave Observatory (Ligo) would "detect gravitational waves by 2010".

The bet was placed at 100/1 by Ladbrokes but the date came and went without the breakthrough and the physicists, based at the University of Glasgow and part of the Ligo project, missed out on any chance of winning £2,500.

But Prof Rowan, director of the university's Institute for Gravitational Research, said it was worth the extra years of waiting.

"That gravitational wave was coming for 1.3 billion years so six years is lost in the noise," she added.

Other possible scientific breakthroughs - including the discover y of the Higgs boson - were offered as bets at the time but the bookmaker slashed the odds on the detection of gravitational waves following a rush of interest.

"I think the book closed at 6/1 and I think the odds were even better earlier in the day - possibly starting off at 500/1," said Prof Rowan.

"We were working towards this but it was interesting to see how much confidence people had back then. The reason those odds dropped and dropped so quickly was that people in our field had confidence that we were going to get to this point and I think it kind of brought that out. It was just a question of when.

"It was certainly worth our money."

The historic announcement made in the US last Thursday confirmed gravity waves - ripples in spacetime - have been detected by scientists a century after Albert Einstein predicted their existence, and it has been described as ''the biggest scientific breakthrough of the century''.